Use of groundwater, reclaimed water, and other impaired water sources is a critical strategy for fresh surface water conservation. Because impaired water desalination by reverse osmosis is energy-intensive, a robust ion-exchange resin wafer electrodeionization technology was developed to conserve energy during impaired water desalination. The loose ion-exchange resin beads were immobilized and molded to form a porous resin wafer material and utilized for impaired water desalination. In this study, the impaired water desalination using resin wafer electrodeionization was evaluated along with various key performance indicators, including current efficiency, energy efficiency, and productivity. Results suggest that resin wafer electrodeionization can improve energy efficiency to >35% in comparison to that of reverse osmosis (normally ∼12%) for impaired water desalination. The energy consumption of resin wafer electrodeionization was found to be 0.354–0.657 kWh/m3 with a productivity of 20.1–41.3 L h–1 m–2 (i.e., 5.3–10.9 gal h–1m–2) for impaired water desalination. To reclaim cooling water at thermoelectric plants in the United States, a huge amount of energy usage (∼400 GWh/day) can be saved, if resin wafer electrodeionization was applied instead of commercial reverse osmosis. We conclude that resin wafer electrodeionization offers the potential for treating impaired water as a source water, which should be viewed as a crucial component in the portfolio of water supply options.